The invention relates to an arc detector for a gas-insulated electrical installation having an elongated sealed enclosure filled with a high dielectric strength gas, comprising an optic light sensor located in said enclosure and an optic fiber to transmit the light signal supplied by the sensor to a processing device located outside the enclosure.
Internal flashover can cause a large amount of damage in an electrical installation, for example in a metalclad substation, when the fault is not detected and cleared quickly. It is state-of-the-art practice to fit photoelectric cells inside the substation to detect the occurrence of an arc at any point in the substation. These systems are complicated and of uncertain reliability.
Another state-of-the-art arc detector makes use of an optic fiber extending inside the substation to collect the light emitted inside the substation and transmit it to a processing unit which controls tripping of the protective circuit breaker. The sensitivity of this detector is limited and the presence of the fiber in the substation imposes constraints and affects the dielectric withstand.
The object of the present invention is to achieve a simple arc detector, able to monitor large volumes of the substation without diminishing the dielectric withstand.